Lake Tschida — storage

Storage now, against this reservoir's own record

59.29 Mm³

Stored, August 2026

7th

Percentile among 77 Augs on record

-19.6%

Against the Aug 1991–2020 average

-18.8%

Change over the 12 months to 2026-08

Storage in August 2026 was lower than almost every other Aug on record, ranked against 77 other Augs held for this reservoir.

Storage, 1949–2026

Monthly mean storage

923 monthly values, 1949 to 2026

Monthly means of the publisher's daily record. Volume, not percentage of capacity — see below for why.

What the shaded periods are (0 events)

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

240 of 923 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 923 would be longer than this page and unusable with a screen reader.
Period	Lake Tschida (Mm³)
October 1949	0.449
February 1950	0.879
June 1950	87.9
October 1950	75.9
January 1951	72.8
May 1951	94.8
September 1951	82.0
January 1952	73.1
May 1952	95.6
September 1952	88.7
January 1953	75.2
April 1953	78.3
August 1953	94.1
December 1953	79.3
April 1954	99.6
August 1954	81.6
December 1954	73.7
April 1955	81.8
July 1955	93.0
November 1955	78.9
March 1956	77.6
July 1956	81.8
November 1956	67.4
March 1957	64.6
July 1957	94.1
October 1957	84.6
February 1958	77.1
June 1958	85.0
October 1958	67.1
February 1959	61.0
June 1959	88.7
October 1959	68.7
January 1960	63.9
May 1960	93.0
September 1960	83.3
January 1961	69.2
May 1961	70.1
September 1961	53.6
January 1962	50.7
April 1962	58.1
August 1962	82.4
December 1962	72.0
April 1963	81.6
August 1963	91.4
December 1963	73.1
April 1964	71.6
July 1964	100
November 1964	78.7
March 1965	77.3
July 1965	93.7
November 1965	76.0
March 1966	90.1
July 1966	98.9
October 1966	83.0
February 1967	81.8
June 1967	96.2
October 1967	70.0
February 1968	68.9
June 1968	81.6
October 1968	69.2
January 1969	69.8
May 1969	93.4
September 1969	84.3
January 1970	78.6
May 1970	130
September 1970	72.1
January 1971	72.4
April 1971	102
August 1971	85.1
December 1971	75.8
April 1972	99.1
August 1972	90.6
December 1972	88.0
April 1973	96.9
July 1973	86.2
November 1973	68.9
March 1974	78.4
July 1974	82.6
November 1974	63.4
March 1975	64.5
July 1975	94.8
October 1975	78.1
February 1976	82.1
June 1976	93.4
October 1976	67.8
February 1977	66.4
June 1977	98.6
October 1977	97.1
January 1978	94.7
May 1978	98.1
September 1978	83.4
January 1979	83.7
May 1979	97.2
September 1979	82.3
January 1980	76.4
April 1980	83.2
August 1980	78.2
December 1980	76.2
April 1981	79.5
August 1981	75.9
December 1981	82.1
April 1982	114
July 1982	94.1
November 1982	96.7
March 1983	100
July 1983	91.8
November 1983	84.6
March 1984	91.5
July 1984	90.3
October 1984	72.2
February 1985	74.3
June 1985	92.8
October 1985	72.0
February 1986	75.8
June 1986	95.5
October 1986	95.3
January 1987	94.7
May 1987	94.3
September 1987	77.2
January 1988	72.3
May 1988	82.4
September 1988	58.6
January 1989	58.7
May 1989	79.1
August 1989	62.1
December 1989	58.4
April 1990	60.5
August 1990	51.4
December 1990	47.5
April 1991	51.2
August 1991	46.4
November 1991	41.1
March 1992	46.5
July 1992	46.4
November 1992	41.4
March 1993	58.2
July 1993	78.4
November 1993	91.8
February 1994	91.8
June 1994	97.1
October 1994	76.7
February 1995	81.6
June 1995	84.9
October 1995	82.0
February 1996	84.8
May 1996	84.8
September 1996	70.9
January 1997	75.8
May 1997	85.8
September 1997	77.5
January 1998	74.5
May 1998	84.2
August 1998	81.4
December 1998	81.9
April 1999	84.4
August 1999	76.6
December 1999	72.9
April 2000	77.9
August 2000	74.6
November 2000	69.8
March 2001	82.4
July 2001	83.7
November 2001	69.8
March 2002	65.2
July 2002	74.3
November 2002	66.1
February 2003	68.2
June 2003	84.3
October 2003	68.0
February 2004	70.0
June 2004	82.3
October 2004	69.8
February 2005	72.9
May 2005	78.4
September 2005	72.4
January 2006	73.1
May 2006	83.5
September 2006	59.8
January 2007	61.3
May 2007	70.7
August 2007	66.6
December 2007	66.1
April 2008	67.0
August 2008	55.8
December 2008	54.7
April 2009	118
August 2009	79.6
November 2009	71.6
March 2010	76.0
July 2010	82.0
November 2010	75.3
March 2011	84.4
July 2011	85.9
November 2011	71.1
February 2012	73.8
June 2012	83.2
October 2012	70.6
February 2013	74.5
June 2013	88.7
October 2013	84.1
February 2014	78.4
May 2014	76.4
September 2014	77.9
January 2015	74.4
May 2015	82.6
September 2015	76.1
January 2016	71.1
May 2016	80.9
August 2016	71.0
December 2016	70.3
April 2017	82.7
August 2017	65.8
December 2017	64.7
April 2018	81.9
August 2018	74.2
November 2018	73.5
March 2019	96.4
July 2019	79.9
November 2019	76.5
March 2020	85.3
July 2020	74.0
November 2020	63.9
February 2021	66.2
June 2021	76.4
October 2021	52.8
February 2022	55.0
June 2022	79.2
October 2022	65.7
February 2023	69.1
May 2023	79.6
September 2023	73.3
January 2024	72.3
May 2024	78.4
September 2024	69.7
January 2025	66.1
May 2025	78.1
August 2025	73.0
December 2025	71.7
April 2026	76.6
August 2026	59.3

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

1991–2020 average
Most recent 12 months

Twelve separate averages, one per calendar month. A January average describes Januaries only. Months are plotted 1–12.

View the data behind this chart

Underlying data
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	69.6	73.8
Feb	70.7	78.5
Mar	78.0	79.0
Apr	81.3	76.6
May	79.0	74.6
Jun	79.5	72.3
Jul	77.3	66.4
Aug	73.7	59.3
Sep	70.4	70.0
Oct	69.8	69.3
Nov	69.9	70.3
Dec	70.2	71.7

Why this page shows a volume and not a percentage

Percentage full is a division, and the denominator is missing

“Percentage full” is the figure a drought is discussed in, and it is stored volume divided by capacity. Capacity is published on several different bases — gross, usable, live, and the figure at a particular spillway or licence condition — and dividing a stored volume by the wrong one produces a percentage confidently wrong by the ratio between them, at exactly the moment the number matters most.

Hydrionis holds storage measurements for this reservoir and does not hold a compatible authoritative capacity figure for it, so percentage full is not calculated. The volume above is what was actually measured. Where you need a percentage, take the publisher’s own capacity on its own stated basis and divide it yourself — the source is linked below, and knowing which basis you used is the whole point.

Water level

Monthly mean water surface elevation

923 monthly values

An elevation above a datum, not a depth of water and not a distance below the crest. Levels at different reservoirs are measured against different datums and must not be read against one another; this line is comparable only with its own history. Elevation and volume are not proportional either — a metre near the bottom of a reservoir holds far less water than a metre near the top, because the surface area grows with height.

What the shaded periods are (0 events)

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

240 of 923 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 923 would be longer than this page and unusable with a screen reader.
Period	Lake Tschida (m)
1949.75	554
1950.0833333333333	614
1950.4166666666667	629
1950.75	628
1951	628
1951.3333333333333	629
1951.6666666666667	628
1952	628
1952.3333333333333	629
1952.6666666666667	629
1953	628
1953.25	628
1953.5833333333333	629
1953.9166666666667	628
1954.25	630
1954.5833333333333	628
1954.9166666666667	628
1955.25	628
1955.5	629
1955.8333333333333	628
1956.1666666666667	628
1956.5	628
1956.8333333333333	627
1957.1666666666667	627
1957.5	629
1957.75	629
1958.0833333333333	628
1958.4166666666667	629
1958.75	627
1959.0833333333333	627
1959.4166666666667	629
1959.75	627
1960	627
1960.3333333333333	629
1960.6666666666667	628
1961	627
1961.3333333333333	627
1961.6666666666667	626
1962	626
1962.25	626
1962.5833333333333	628
1962.9166666666667	628
1963.25	628
1963.5833333333333	629
1963.9166666666667	628
1964.25	628
1964.5	630
1964.8333333333333	628
1965.1666666666667	628
1965.5	629
1965.8333333333333	628
1966.1666666666667	629
1966.5	630
1966.75	628
1967.0833333333333	628
1967.4166666666667	629
1967.75	627
1968.0833333333333	627
1968.4166666666667	628
1968.75	627
1969	627
1969.3333333333333	629
1969.6666666666667	629
1970	628
1970.3333333333333	632
1970.6666666666667	628
1971	628
1971.25	630
1971.5833333333333	629
1971.9166666666667	628
1972.25	630
1972.5833333333333	629
1972.9166666666667	629
1973.25	630
1973.5	629
1973.8333333333333	627
1974.1666666666667	628
1974.5	628
1974.8333333333333	627
1975.1666666666667	627
1975.5	629
1975.75	628
1976.0833333333333	628
1976.4166666666667	629
1976.75	627
1977.0833333333333	627
1977.4166666666667	630
1977.75	630
1978	629
1978.3333333333333	630
1978.6666666666667	629
1979	629
1979.3333333333333	630
1979.6666666666667	628
1980	628
1980.25	628
1980.5833333333333	628
1980.9166666666667	628
1981.25	628
1981.5833333333333	628
1981.9166666666667	628
1982.25	631
1982.5	629
1982.8333333333333	629
1983.1666666666667	630
1983.5	629
1983.8333333333333	629
1984.1666666666667	629
1984.5	629
1984.75	628
1985.0833333333333	628
1985.4166666666667	629
1985.75	628
1986.0833333333333	628
1986.4166666666667	629
1986.75	629
1987	629
1987.3333333333333	629
1987.6666666666667	628
1988	628
1988.3333333333333	628
1988.6666666666667	626
1989	626
1989.3333333333333	628
1989.5833333333333	627
1989.9166666666667	626
1990.25	627
1990.5833333333333	626
1990.9166666666667	625
1991.25	626
1991.5833333333333	625
1991.8333333333333	625
1992.1666666666667	625
1992.5	625
1992.8333333333333	625
1993.1666666666667	626
1993.5	628
1993.8333333333333	629
1994.0833333333333	629
1994.4166666666667	630
1994.75	629
1995.0833333333333	629
1995.4166666666667	629
1995.75	629
1996.0833333333333	629
1996.3333333333333	629
1996.6666666666667	628
1997	629
1997.3333333333333	629
1997.6666666666667	629
1998	629
1998.3333333333333	629
1998.5833333333333	629
1998.9166666666667	629
1999.25	629
1999.5833333333333	629
1999.9166666666667	628
2000.25	629
2000.5833333333333	629
2000.8333333333333	628
2001.1666666666667	629
2001.5	629
2001.8333333333333	628
2002.1666666666667	628
2002.5	629
2002.8333333333333	628
2003.0833333333333	628
2003.4166666666667	629
2003.75	628
2004.0833333333333	628
2004.4166666666667	629
2004.75	628
2005.0833333333333	628
2005.3333333333333	629
2005.6666666666667	628
2006	629
2006.3333333333333	629
2006.6666666666667	627
2007	628
2007.3333333333333	628
2007.5833333333333	628
2007.9166666666667	628
2008.25	628
2008.5833333333333	627
2008.9166666666667	627
2009.25	631
2009.5833333333333	629
2009.8333333333333	628
2010.1666666666667	629
2010.5	629
2010.8333333333333	629
2011.1666666666667	629
2011.5	629
2011.8333333333333	628
2012.0833333333333	629
2012.4166666666667	629
2012.75	628
2013.0833333333333	629
2013.4166666666667	630
2013.75	629
2014.0833333333333	629
2014.3333333333333	629
2014.6666666666667	629
2015	629
2015.3333333333333	629
2015.6666666666667	629
2016	628
2016.3333333333333	629
2016.5833333333333	628
2016.9166666666667	628
2017.25	629
2017.5833333333333	628
2017.9166666666667	628
2018.25	629
2018.5833333333333	629
2018.8333333333333	629
2019.1666666666667	630
2019.5	629
2019.8333333333333	629
2020.1666666666667	629
2020.5	629
2020.8333333333333	628
2021.0833333333333	628
2021.4166666666667	629
2021.75	627
2022.0833333333333	627
2022.4166666666667	629
2022.75	628
2023.0833333333333	628
2023.3333333333333	629
2023.6666666666667	629
2024	629
2024.3333333333333	629
2024.6666666666667	628
2025	628
2025.3333333333333	629
2025.5833333333333	629
2025.9166666666667	629
2026.25	629
2026.5833333333333	627

Rate and persistence

-1.14 Mm³

Mean drawdown per month over 12 months

9 of 24

Recent months below the 20th percentile for their own month

Rates are computed only across an unbroken run of months, so a rate is never divided by a period in which some of the change was not observed. Percentile counts compare each month with the same calendar month in every other year held.

Location

Lake Tschida

Gauge location

About this data

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Bureau of Reclamation — Reservoir operations and Colorado River data · US Government work — public domain
How the values came to exist	Measured
Period held	1949–2026
Completeness	98.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	Storage is a managed quantity. A falling line can be a rule curve, a scheduled release or a transfer to another system rather than a shortage of water, and nothing here distinguishes them. No capacity figure on a stated basis is held for this reservoir, so no percentage of capacity is computed.
Continuity	99% of the months between 1949 and 2026 are held. Monthly means of the publisher's own daily record.
Last read from the publisher	2026-09-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

Use this data

Machine-readable JSON /api/v1/observations/by-subject/reservoir-usbr-402.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Suggested citation for Hydrionis

Hydrionis (2026), Lake Tschida reservoir records, accessed 2026-09-02, hydrionis.com/reservoirs/reservoir-usbr-402/

Cite Hydrionis where you rely on the compilation, the normalisation, the eligibility judgements or a chart. Where you use an unmodified published value, the publisher’s attribution is the one that is required; crediting Hydrionis as well is welcome and is not something Hydrionis can require of you.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the Lake Tschida record changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where this comes from

923 monthly observations 1949–2026 Mm³

Spatially aggregatedHigh confidenceAugust 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 549. Licence: Open.

Method: Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Stored as a volume and not as a share of capacity: the operator publishes what is in the reservoir but not what it holds when full, so a percentage cannot be computed without inventing the denominator.

Retrieved 1 September 2026.

Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.